1. Technical Field
The present invention relates to an image processing method, an image processing apparatus, and an image processing program related to processing of converting image data into print data, and a printing system.
2. Related Art
In an image processing apparatus which outputs general image data of RGB obtained by a digital camera, or the like, by converting the image data into print data for performing printing in an ink jet printer, as a method of converting multi-grayscale image data into binarized print data, an error diffusion method, for example, is used. The error diffusion method is a method in which a quantization error when binarizing a target pixel is diffused to a grayscale value of a pixel in the vicinity of the target pixel which is not subjected to binarization, and each grayscale value thereof is successively binarized.
Since data conversion processing using the error diffusion method is performed while diffusing a quantization error one after another, it is possible to form a dependency relationship in data processing with respect to data in a diffusion destination, and it is necessary to continuously perform conversion processing in series, in a range in which the dependency relationship is present. As a result, for example, in a case in which an image becomes large, and becomes an image with high resolution, the number of pixels to be continuously processed in series increases, and accordingly, a processing time becomes long.
In a case of processing large image data which exceeds a size of a memory space for performing data processing, in many cases, the processing proceeds while dividing the image data into an allowable size. With respect to the above described problem, in JP-A-2011-95807, an image processing apparatus and an image processing method are described, in which it is possible to process divided image data in parallel in a dependency direction of data processing, by setting a division direction thereof to a direction orthogonal to a direction in which a dependency relationship in data processing is present, when dividing the image data, and as a result, it is possible to improve throughput of data processing.
However, in the image processing apparatus and the image processing method which are described in JP-A-2011-95807, there is a problem in that a dependency relationship in data processing, that is, a direction for performing an error diffusion is limited in order to make a division of image data possible, and depending on a direction in which a division is possible. In addition, there is a problem in that, in a case in which a direction of proceeding printing sequentially is orthogonal to a direction in which image data is divided, it is not possible to start printing until conversion processing of the entire image data is completed, in a case of a printing apparatus which performs printing while sequentially receiving converted print data.